This invention relates to a brake control apparatus and a brake control method which are configured to increase a pressure of a wheel cylinder by a pump.
US Patent Application Publication No. 2006-0119173 (corresponding to Japanese Patent Application Publication No. 2006-159949) discloses a brake control apparatus including a pump arranged to increase pressures of wheel cylinders not by intension of a driver. The brake control apparatus is arranged to perform an automatic brake control such as an anti skid control, a vehicle behavior control, and an inter-vehicular distance control (following-distance control).
In this brake control apparatus, the wheel cylinder pressures are larger than the master cylinder pressures during the automatic brake control by increasing the pressure by the pump. In this state, when the brake pedal is depressed, the hydraulic fluid within the master cylinder is not discharged. Accordingly, the brake pedal does not perform the stroke or does not move. It becomes a stiff brake pedal state in which the driver may feel like depressing a hard or stiff plate (in which the brake pedal stroke is hardly caused when the brake pedal is depressed). Accordingly, the brake control apparatus includes a reservoir arranged to absorb the hydraulic fluid discharged from the master cylinder, and a cut valve arranged to connect or disconnect between the reservoir and the master cylinder. When brake pedal BP is depressed during the pressure increase by the pump, the cut valve is opened to connect the master cylinder and the reservoir. With this, the pedal stroke is ensured by discharging the hydraulic fluid by the pedal stroke operation when it becomes a brake override state in which the brake pedal is depressed during the brake control.